MEASURING AND TESTING MACHINES AND OSCILLOSCOPE FOR MEASURING SIZES, WEIGHTS, AND TIME, AND FOR MEASURING WAVEFORMS; ELECTRICAL POWER DISTRIBUTION AND CONTROL MACHINES AND APPARATUS, NAMELY, DC POWER SUPPLIES FOR SUPPLYING AND CONTROLLING POWER DISTRIBUTION FOR ELECTRIC SWITCHBOARDS, SYSTEM RACKS, ELECTRICAL CIRCUITS AND SERVERS; TELECOMMUNICATION DEVICES AND APPARATUS, NAMELY, DC POWER SUPPLIES FOR SERVERS IN COMMUNICATION BASE STATIONS; ELECTRONIC MACHINES, APPARATUS AND STRUCTURAL PARTS THEREFOR, NAMELY, DC POWER SUPPLIES, HIGH VOLTAGE POWER SUPPLIES AND ELECTRONIC X-RAY APPARATUS FOR NON-MEDICAL PURPOSES; OZONISERS AND STRUCTURAL PARTS THEREFOR, NAMELY, DC POWER SUPPLIES FOR OZONIZERS; ELECTROLYZERS AND STRUCTURAL PARTS THEREFOR, NAMELY, DC POWER SUPPLIES FOR USE IN METAL PLATING AND ELECTROLYSIS; ELECTRIC ARC WELDERS; ELECTRIC WELDING APPARATUS, NAMELY, DC AND AC POWER SUPPLIES FOR WELDING MACHINES